Enter the change in shock position (in) and the change in wheel position (in) into the Motion Ratio Calculator. The calculator will evaluate and display the Motion Ratio. 

Motion Ratio Formula

The following formula is used to calculate the Motion Ratio. 

MR = dS / dW
  • Where MR is the Motion Ratio ( )
  • dS is the change in shock position (in) 
  • dW is the change in wheel position (in) 

To calculate the motion ratio, divide the change in shock position by the change in wheel position.

How to Calculate Motion Ratio?

The following example problems outline how to calculate Motion Ratio.

Example Problem #1:

  1. First, determine the change in shock position (in).
    • The change in shock position (in) is given as: 2.5.
  2. Next, determine the change in wheel position (in).
    • The change in wheel position (in) is provided as: 4.
  3. Finally, calculate the Motion Ratio using the equation above: 

MR = dS / dW

The values given above are inserted into the equation below and the solution is calculated:

MR = 2.5 / 4 = .625


What is the importance of calculating the Motion Ratio in vehicle dynamics?

The Motion Ratio is crucial in vehicle dynamics as it directly affects the vehicle’s handling and ride comfort. By understanding the Motion Ratio, engineers can design suspension systems that offer an optimal balance between comfort and handling, ensuring that the vehicle performs well under various driving conditions.

Can the Motion Ratio vary for different types of vehicles?

Yes, the Motion Ratio can vary significantly between different types of vehicles due to variations in suspension design, vehicle weight, and intended use. For example, a sports car may have a different Motion Ratio compared to a heavy-duty truck because each vehicle is designed with specific performance goals in mind.

How does changing the Motion Ratio affect a vehicle’s performance?

Changing the Motion Ratio can have a profound impact on a vehicle’s performance. A higher Motion Ratio means that the suspension is more responsive to wheel movement, which can improve handling but may also result in a firmer ride. Conversely, a lower Motion Ratio can lead to a softer ride at the expense of handling precision. Therefore, finding the right balance is key to achieving the desired performance characteristics.